Synthetic pathways leading to model compounds 25, 27, 33, 20d, 32b, 37, and 42 for the marine alkaloids, herbindoles and trikentrins (1b-i), are presented. p-Toluenesulfonic acid-mediated indole cyclization reactions, 19→20 and 38→39, assisted with thiols such as benzylthiol or thiophenol, are key steps for preparation of the compounds having the 1, 6, 7, 8-tetrahydrocyclopent[g]indole structure. Novel reactions of the phenylsulfone group in 20c and 20e with allyltrimethylsilane in the presence of dichloroethylaluminum as well as with trimethylaluminum, are explained in terms of participation of an intermediary reactive species 29.
对甲苯磺酸介导的
吲哚环化反应 19→20 和 38→39 在巯基(如
苄硫醇或
噻吩酚)的辅助下进行,是制备具有 1,6,7,8-四氢环戊[g]
吲哚结构的化合物的关键步骤。20c 和 20e 中的苯砜基团与烯丙基三甲基
硅烷在
二氯乙基铝以及
三甲基铝存在下发生的新反应,可以用中间反应物 29 的参与来解释。